1. Field of the Invention
Embodiments of the invention are in the field of clustered computer systems, and more specifically, relate to techniques for changing a resource dynamic link library (DLL) in a clustered computer system.
2. Description of Related Art
A cluster is a group of computers that work together to run a common set of applications and appear as a single system to the client and applications. In a traditional cluster, the computers are physically connected by cables and programmatically connected by cluster software. These connections allow the computers to use failover and load balancing, which is not possible with a stand-alone computer.
A clustered system typically has a variety of resources. Clustered resources may include a disk drive, a logical unit on redundant arrays of inexpensive disks (RAIDS) subsystem, an Internet Protocol (IP) address, a network name, an application program, etc. Many clustered systems allow the management of clustered resources in a separate executable library associated with a resource, referred to as a resource dynamic link library (DLL).
When a resource DLL is changed, e.g., upgraded, updated, modified or replaced with a newer version, the associated resource is taken off line or moved to another member computer in the clustered system during the change process. In some clustered systems, each member computer may have to be re-booted in order to complete this resource DLL change process. In a high-availability environment, such as that of a clustered system, such a temporary unavailability of a resource or system interruption may not be acceptable.
Thus, it is desirable to have a technique to provide availability in a clustered system during a change of a resource DLL.